As of Tuesday, the U.S. and its coalition partners had conducted nearly 310 air attacks on Islamic terrorist targets, more than 230 in Iraq and 76 in Syria, a Pentagon spokesman said.

And while the air campaign has forced the terrorists to change their tactics, “We still believe ISIL remains a very potent force,” Admiral John Kirby told reporters on Tuesday.

“Yes, they’ve changed some of their tactics, there’s absolutely no question about that, in response to the pressure that we put them under, but that doesn’t make them less dangerous or less potent over time,” Kirby said.

That doesn’t sound like it accomplished very much. It gets worse when you factor in how much it cost. According to the Washington Times,

Defense analysts in the nation’s capital estimate the three-month tab for U.S.-led airstrikes at close to $1 billion.

An independent analysis conducted by the Center for Strategic and Budgetary Assessments concluded that the U.S. spent $780 million to $930 million targeting the Islamic State group through Sept. 24, Military.com reported Tuesday.

The center’s independent analysis of airstrike spending said, “The cost of future operations depends primarily on how long operations continue, the intensity of air operations, and whether additional ground forces are deployed beyond what is already planned,” the website reported.

Depending on whether the Obama administration adopts a low- or high-intensity posture as airstrikes continue, analysts said, the federal government will need to provide the Pentagon with $2.4 billion to $6.4 billion per year.